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104 Cards in this Set
- Front
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Define Gene |
Heritable factorconsisting of a length of DNA that controls a specific trait |
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Define Locus (Loci) |
Genesconsist of a length of DNA occupying a particular position/location on achromosome |
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Define Alleles |
Variousspecific forms of a gene (alternate forms that differ from each other but oneor few nitrogen bases). New alleles formed via mutations |
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Define Mutation |
Random,rare change in genetic material (DNA). Can be positive (increase chance ofsurvival), negative (decrease it), or neutral/silent (no effect) |
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What is a Base-Substitution Mutation? |
Mutationdue to a single nitrogen base change in a DNA sequence, meaning a new aminoacid is placed on the polypeptide chain (could have no/little effect or hugeconsequences) |
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What is a Genome? Genome Size? |
The whole of the geneticinfo of an organism, consisting of DNA (or RNA in viruses), both coding andnon-coding sequences of genes. Genome size: total # of DNAbase pairs in one copy of a haploid genome |
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What is the Human Genome Project? What was the goal? |
Ten-yeareffort (1993-2003) to discover the complete set of human genes and make themaccessible for further biological study. Goal was achieved. |
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What are the characteristics (or features) of a plasmid?
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- Naked DNA – notassociated with histones - Small circular ring - Not responsible fornormal life processes - Can be passed betweenprokaryotes - Can be incorporationinto nuclei chromosome - Useful in geneticengineering, used to transfer genes into bacteria |
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What are homologous chromosomes? |
Carry same sequence ofgenes but not necessarily the same alleles of those genes Paired chromosomes thatcome from each parent Replicate during S-phaseof interphase, resulting in 2 pairs of sister chromatids each joined at acentromere Homologs associateduring prophase I through synapsis, make bivalent (or: tetrad) |
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Diploid Nucleus vs. Haploid Nucleus |
Diploid: Has two of eachchromosome (2n), two copies of each gene (except sex chromosomes) called sisterchromatids, only known as separate chromosomes after having been split inanaphase (cell division) Haploid: Hasone of each chromosome (n), in gametes |
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Karyogram vs. Karyotype |
Karyogram: Diagram/photographof chromosomes present in nucleus arranged in homologous pairs in decreasinglength. This diagram shows/can be used to determine a karyotype Karyotype: Property of celldescribed by number & type of chromosomes in the nucleus (only visiblewhile cell is undergoing mitosis, stains used to make banding patterns visible,micrograph is taken and chromosomes arranged according to size, bandingpattern, position of centromere, etc.) |
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Define Meiosis |
A form of cell division that is a reduction division of the nucleus to form haploid gametes from diploid cells |
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What are sister chromatids? |
Clonedchromosomes, two identical strands joined by common centromere as a result ofchromosome that duplicated during S-phase of the cell cycle |
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What is random orientation? When does it occur? |
Thebehaviour of homologous pairs for chromosomes (metaphase I) or pairs of sisterchromatids (metaphase II) lining up randomly at the equator in meiosis |
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What is independent assortment? When does it occur? |
The behaviour of allelesof unlinked genes as a result of gamete production (meiosis II) Law of IndependentAssortment: the presence of an allele of one of the genes has no influence overwhich allele of another gene is present. Genes must be unlinked for this to betrue. |
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What is non-disjunction? |
Whenhomologous chromosomes fail to separate correctly during anaphase I or II,resulting in either one extra chromosome (trisomy, 3 instead of 2) or one lesschromosome (monosomy, 1 instead of 2) |
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What is Trisomy 21? What is the risk of having a child with this disorder? How can a mother-to-be know if her child has it? |
Down syndrome, an individual possesses 3 of chromosome 21 (has 47 chromosomestotal instead of 46)Risk of having child withtrisomy increases greatly in older mothers, which is why it’s recommended forhigh-risk mothers to have a prenatal test to determine whether or not the childis healthy. After that, mother’s choice whether shewants to continue the pregnancy |
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What does it by "every living organism inherits a blueprint for life from its parents"? |
Genetic info inheritedfrom parents 50% for mother and 50%from father Combos of genesinherited by each offspring will be different |
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Does the number of chromosomes of an individual reflect complexity? |
No. Other than number of chromosomes, organ systems, brain development and stimulus and response must also be considered. Ex. grapes and water fleas both have more chromosomes than humans, but this doesn't make them more complex. |
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State and explain the cause of one base-substitution mutation. Include positive and/or negative consequences. |
Cause: Base substationmutation that causes glutamic acid to be replaced with valine as the 6thamino acid in the hemoglobin protein. This causes the blood cell to appearsickle-like Cons: Sicklecells block blood flow, transport less oxygen, lead to many health problemsincluding death Pro: immune to malaria as it cannot invade sicklecells, only normal red blood cells |
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What do all individuals of a species have in common? |
They all possess the same number of chromosomes with the same genes (could be different alleles) at the same loci. Organisms with different chromosome numbers cannot interbreed successfully. |
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What is the difference between prokaryotic DNA and eukaryotic DNA? |
Prokaryotic: only one circular DNA in nucleoid region because reproduce asexually Eukaryotic: come in pairs (one from each parent), linear, supercoil during cell division |
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Chromosomes can vary by...? (3 factors) |
- Length (or number of base pairs) - Position of the centromere - Types of genes and their specific locus |
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How is sex determined? |
XX = female XY = male Therefore, presence of Ychromosome determines gender because it contains the SRY gene that leads tomale development. Without it, it will be a female by default Note: X is much larger and hasmany more genes than Y |
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What was John Cairns known for? |
Measuring DNA molecule length by Autoradiography |
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What is Autoradiography? |
E. Coli growth withthymidine (DNA labeled) Cells were broken openby enzymes to release contents Contents then applied tophotographic emulsion and placed in the dark for 2 months Dark areas onphotographic emulsion = presence of DNA Image showed that E. Colihad one single circular DNA strand that was much longer than thebody of the E. Coli was |
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What are the characteristics of mitosis? (8 things) |
- 1 division - Diploid cells produced - No crossing over - No chiasmata - Homologs don't associate - Sister chromatids separate (Anaphase) - Body (Somatic) cells formed - Diploid to diploid |
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What are the characteristics of meiosis? (8 things) |
- 2 divisions - Haploid cells produced - Chiasmata form - Crossing over may occur (prophase I) - Homologs separate AND sister chromatids separate - Sex cells (gametes) formed - Diploid to haploid |
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What is the significance of halving the chromosome number? Explain in terms of fertilization. |
Because fertilization involves fusion ofgametes, the # of chromosomes in the next generation is doubled To prevent doubling of chromosomes in eachgeneration: a halving mechanism needed during life cycle To compensate for chromosomes doubling during fertilization, gametesundergo meiosis (halves the chromosomes present in gametes compared to theparent) |
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What occurs during Interphase? |
S-phase:chromosomes replicate, these copies attach at centromere (sister chromatids) Furthergrowth and preparation for cell division take place after S phase |
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How does crossing over occur? What are the three events? |
- Synapsis :Homologs associate into bivalents - Chiasmata Formation: Neighbouringnon-sister chromatids in a bivalent are broken at the same point, Ajunction forms as the DNA of the broken sections attach to the open end of theopposite non-sister chromatid - Recombination: Endresult: alleles swapped between non-sister chromatids, new gene combinationsformed. This increases geneticvariation between gametes |
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Describe what happens during prophase I of meiosis. |
- Homologs associate into bivalents - Centrioles migrate to opposite poles - Nuclear membrane dissolves - Crossing over may occur |
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What are the events of metaphase I? |
Bivalentsline up randomly (random orientation) at the equator and hence the daughter nuclei get a differentmix of chromosomes every time |
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What happens during anaphase I? |
Homologouspairs are separating and pulled (by spindle microtubules shortening,contracting) to opposite poles of the cell This is the reductiondivision (diploid to haploid) |
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What are the events of telophase I? |
- Cytoplasm begins to divide (cytokinesis) - Two nuclei form - Chromosomes uncoil - Nuclear membrane reforms |
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What are the events of prophase III? |
- Nuclearmembranes dissolve - Chromosomesconsisting of sister chromatids condense (supercoil) - Nocrossing over - Centriolesmove to opposite poles |
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What happens during metaphase II and anaphase II? |
Metaphase II: - Pairs of sister chromatids align on the equator (randomly) Spindle fibres form and attach at centromeres Anaphase II: - Spindlefibres contract, shorten, centromeres splits, sister chromatids split (each nowcalled chromosomes) pulled to opposite poles |
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Describe the events of telophase II? |
- Nuclear membranes reform - Chromosomes uncoil - 4 haploid nuclei formed (gametes) - Cytokinesis begins splitting the cells - Fertilization of haploid gametes will produce diploid cells |
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In what three ways does meiosis promote genetic variation? Why is this important? |
- The combination of both crossing over and random orientationresults in pretty much infinite variety in haploid gametes - Plus, meiosis occurs in both parents that reproducesexually, increasing variation even more, meaning fusion of gametes fromdifferent parents (fertilization) also promotes variation - Increased genetic variation produces a more resilientpopulation, more likely to withstand environmental change such e.g. disease.Genetic variation essential for successful evolution |
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Name the two methods of obtaining fetal cells for karyotype analysis. |
1. Amniocentesis 2. Chorionic Villus Sampling |
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What is amniocentesis? What is the associated risk? |
Sample of amniotic fluidcontaining fetal cells taken using syringe These fetal cells arethen used for karyotyping Risk: miscarriage because of damage to the amniotic sac |
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What is chorionic villus sampling? What is the associated risk? |
Chorion: membrane whichis a part of the placenta, containing many cells with villi Needle in insertedthrough vagina into uterus and a sample is taken, cultured, and used forkaryotyping Risk: miscarriage |
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What is the Law of Dominance? |
Incases where two or more forms of a gene exist for a single trait, some forms ofthe gene may be dominant and others recessive (i.e. an organism with alternateforms of a gene will express the form that is dominant) |
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Dominant vs. recessive |
Dominant: Formof allele that is expressed, masks recessive allele Recessive: Individualshave two alleles for each gene and when gametes form during meiosis, the 2alleles separate, each resulting gamete ending up with only one allele of eachgene |
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What is the Law of Segregation? |
Individualshave two alleles for each gene and when gametes form during meiosis, the 2alleles separate, each resulting gamete ending up with only one allele of each gene. |
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Discuss in detail the LAW of Independent Assortment. |
- Whengametes are formed, each pair of alleles for a particular trait separatesindependently of other parts of genes (Only true if genes are NOT linked toeach other, must be on separate chromosomes) - Theseparation of one pair of alleles between daughter cells is independent ofseparation of another pair of alleles (one allele doesn't follow another whenpassed onto a gamete) - Genesfor different traits are sorted separately from one another – inheritance of 1 traitis not dependent on the inheritance of another trait |
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What is a genotype? Which is the only genotype that ca be known without knowing family history? What is a Phenotype? |
Genotype: Symbolicrepresentation of alleles possessed by an organism, typically represented bytwo letters (Ex. Bb, GG, yy). Theonly genotype that can be known for certain without knowing parental phenotypesor genotypes is the homozygous recessive one. Phenotype : Observable characteristicsof an organism (Ex. Type O blood, colour blindness, etc.) |
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What are dominant, recessive and codominant alleles? |
Dominant: Anallele that has the same effect on the phenotype whether paired with sameallele or different, always expressed in the phenotype Recessive: Allelethat only has an effect on the phenotype when present in the homozygousrecessive state Codominant: Pairof alleles that both affect the phenotype when present in a heterozygous state |
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Homozygous vs. heterozygous? |
Homozygous: Twoidentical alleles of a gene (Ex. AA, homozygous dominant, or aa, homozygousrecessive) Heterozygous: Twodifferent alleles of a gene, resulting from maternal and paternal alleles beingdifferent from each other (Ex. Aa) |
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What is a carrier? |
Individualthat HAS a recessive allele in the genotype, but it is not expressed in thephenotype as it is masked by the dominant allele. However, recessive allelecould be expressed in offspring depending on which allele the other parent has |
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What are gametes? What is the significance of their fusion? |
Haploidcells, resulting from reductive division, and only contain one allele of eachgene because the two alleles separate in Anaphase II of Meiosis Fusion of gametes(fertilization) restores chromosome number and allelic pairs combine, may bedifferent from each other. |
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Sex chromosomes vs autosomal chromosomes? |
Sex chromosomes: Thechromosome pair which helps in determining the gender of an organism Autosomal: Akaautosomes, all the chromosomal pairs which are not sex chromosomes |
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Define Linked Genes and Linkage Group. |
Linked genes: Linkedif gene loci are on the same chromosome, inherited together, do not assortindependently. Linkage group:vGroupof genes to be inherited together as a result of their location on the samechromosome. NOTE: Only way to separatelinked genes is through recombination (crossing over during synapsis) |
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Define polygenic inheritance and epistasis. Give examples. |
Polygenic inheritance: when multiple genes in different loci (could be on different chromosomes are responsible for one phenotype. Results in continuous variation from one extreme to the other, ex. skin colour in humans Epistasis: Maskingof a phenotypic effect of alleles by alleles of another gene. Gene is epistatic when its presence suppresses the effect of another gene at anotherlocus (dominant or recessive) Ex. Albinism |
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Explain discrete variation in detail. Include an example. |
Individualsfall into a number of distinct classes/categories and is based on features thatcannot be measured across a complete range. You either have the trait or you donot. Controlled by alleles of a single/small number of genes. The environmenthas little to no effect on this type of variation. Ex. Blood groups |
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Explain continuous variation in detail. Include Examples. |
Complete range of measurement from one extreme to the other. Height is an example - complete range. Other examples include weight, hand span, skin colour, shoe size, etc. |
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Why was Mendel's pea plant experiment significant? |
- Plantedthousands of seeds per trial, carried out many trials - Workwith peas explained the mechanism of gene inheritance and the basis forunderstanding heredity - Discovered fundamental lawsof inheritance, deduced that genes come in pairs and are inherited distinctly,one from each parent. He tracked segregation of parental genes and theirappearance in offspring as dominant or recessive (recognized mathematicalpatterns of inheritance from one generation to next) |
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Name Mendel's Three Laws |
1. Law of Dominance 2. Law of Segregation 3. Law of independent assortment |
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When making quantitative measurements, why is it important to include many replicates in your data? |
This ensure reliability. Having numericaldata isn’t enough, must be large enough to be reliable (in smaller samples,anomalies more likely to mess up calculated means and standard deviation) |
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What is a test cross? State the test cross procedure outline. |
Used todetermine dominant genotypes of unknown individuals: unknown is crossed withknown homozygous recessive If anyoffspring show the recessive trait, then the individual must be a hybrid(heterozygous) If alloffspring show the dominant trait, then the individual must be purebred(homozygous dominant) |
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What increases the rate of mutation and what are some negative consequences of them? |
Mutationsthat occur in the body (somatic) cells remain within he organism, but mutations that occur in gamete cells can be inherited by offspring: how genetic diseasesarise. Mutation rate increases byradiation and mutagenic chemicals and can cause cancer and other geneticdiseases. |
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What is Cystic Fibrosis? |
- Recessiveautosomal disorder - Bothparents must pass on a defective gene for any of their offspring to get thedisease - Ifchild inherits only one copy, they are a carrier and may pass it onto theirchildren but unaffected by the disease themselves - Affects respiratory anddigestive systems because of defective gene on chromosome 7 called CFTR |
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What is Huntington's Disease? |
Dominantautosomal disorder: only need one dominant allele to be affected by the disease Inheritedbrain disorder, causes cells in parts of the brain to die (progressivebreakdown of nerve cells), person becomes less able to control movements,recall events, make decisions, control emotions, etc. Leads to incapacitationand eventually death.Most people with thedisease develop signs/symptoms in their 30s, 40s, but the onset of disease maybe earlier or later in life |
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What are some consequences of radiation after the nuclear bombing of Hiroshima? |
- Radioactiveisotopes released into the environment exposing humans and other organisms topotentially dangerous levels of radiation - A large area ofpine forest turned brown and died - Horses, cattlenear plant died from radiation damage to their thyroid glands – contaminatedmeat was banned from sales for years afterwards - Drinking water(and milk) contaminated with radioactive iodine, at least 6000 thyroid cancer |
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What are some consequences of radiation after the accident at Chernobyl? |
- Elevated rate ofleukemia (with greatest impact on children and young adults) - Elevated ratesof other cancers - Firestorm incinerating everything within 4.4miles of ground zero - “Black rain” caused contamination even inareas remote from explosion - Hair loss caused by exposure to radiation - Severe burns, keloids (scarring) from thermalradiation |
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What are the general rules when drawing pedigrees? |
- Males = squares, Females = circles - Inmarriages, males are on left, females on right,connected by a horizontal line - Generationsrepresented by roman numeral on the left - Childrenappear in chronological order of birth below the parents as a family line,numbered numerically - Agenotype for each person is listed below each circle/square - A shaded square or circleshows an individual that has the trait studied. - Sex-linked traitsmust be half-shaded to show carriers in females |
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Autosomal vs. Sex-Linked Pedigrees |
Autosomal: - Genders equally affected - Either parent can pass to either child - Male to male transmission Sex-Linked: - males affected more - mothers to sons, dads to daughters - no male to male transmission |
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Dominant vs. Recessive Pedigrees |
Dominant: - Affected child must have one affected parent - Disorder never skips generations - No carriers Recessive: - Affected child can have unaffected parents (disorder can skip generations) - Carriers of disorder present |
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What are the seven types of test crosses? |
1. Monohybrid 2. CoDominant 3. Multiple Alleles (Blood Types) 4. Sex-Linked 5. Dihybrid (Unlinked) 6. Linked Genes (Dihybrid) 7. Polygenic Inheritance |
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What is DNA profiling? |
Techniqueby which individuals are identified on basis of respective DNA profiles. |
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What is gel electrophoresis? |
- Used to separate fragments of DNA according to size by enzymes that cut DNA fragments into varying sizes - Fragments placed into wells of porous agarose gel, which is there exposed to electric current. Heavy big fragments stick close to wells, lightest fragments travel further. - Fragments separate from each other and form a unique banded pattern of DNA (this is called DNA fingerprint orDNA profile) |
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Reproductive vs. Therapeutic Cloning. |
Reproductive: Occurs when a copy of another human is createdthrough SCNT, allowed to grow up to 14 days in petri dish. Newly created embryo is placed back into uterus when it can implant and develop until birth (scientistsallow the clone to live)Ex. Dolly the sheep Therapeutic: Occurs when cloned embryos allowed to grow for only a few days. Embryo created in similar way to reproductive cloning, however theresulting “clone” remains in petri dish, not implanted into uterus, and stemcells are harvested thus “killing” the embryo |
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Define Gene Pool. |
Totalcollection of different alleles in an interbreeding population It changes over time with environmental changes |
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Define Allele Frequency. What is the effect of new combination of alleles on the green pool? |
The proportion of allcopies of a gene that is made up of a specific gene variant (allele) Evolution requires thatallele frequencies change with time in populations. New combos of alleles leadto new phenotype variation via natural selection, thealleles for beneficial adaptations will be likely to be inherited, gene poolchanges over generations |
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Explain the evolution rate theory of Gradualism. Give an example to support your answer. |
- Continuous change at aconstant rate over long periods of time, result of gradual accumulation ofmutations/variations - Fossil record withgradual change and intermediate forms support this theory - Ex. Evolution of modernhorse, gradual change in foot structure and size with changing habitat |
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Explain the evolution rate theory of Punctuated Equilibrium. What evidence is present that supports this theory? |
- Evolution proceedsrapidly in bursts for short periods of time because of sudden environmentalchanges, and has long periods of stability in between where organisms are well suitedto the environment and have no need to evolve - Gaps in fossil record andlack of intermediate forms for many species support this theory, as well asstrata in fossil record showing appearance of many new species after massextinction |
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What is polyploidy? Where is it more common and what is the end result? |
- Condition where organismhas two or more complete sets of chromosomes in al somatic cells, may occur asa result of failure of meiotic cell to undergo cytokinesis (chromosomereplication occurs but cell division does not) - More common in plants –they lack specific sexes and can asexually reproduce (self-pollination)Result: gametes arediploid, offspring are tetraploid aka speciation has occurred,new species that can no longer mate with diploid organisms (triploid offspringtend to be infertile) |
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What is polymerase chain reaction (PCR) used for? |
- Technique using a machine called athermocycler (takes a very small quantity of DNA, copies all the nucleic acidsin it to make millions of copies). Amplifies small samples of DNA - PCR used to solve problem of how to get enoughDNA to be able to analyze it, ex. crime scene sample of blood, semen, tissue, hair, etc. |
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What are some techniques that biologists developed for artificial manipulation of DNA (cells and organisms)? |
- Copying DNA in a lab (PCR) - DNA Profiling: using DNA to reveal identity - Mapping DNA: Gene Sequencing (Human Genome Project) - Gene Transfer: Cutting/pasting to make new organisms - Cloning cells and animals |
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Discuss Satellite DNA in detail. |
- Within the non-codingregion of an individual’s genome, there exists satellite DNA – long stretchesof DNA made up of repeating elements called short tandem repeats (STRs) - These repeatingsequences can be excised to form fragments by cutting with a variety of restrictionendonucleases (which cut DNA at specific sites) - Asindividuals all have a different number of repeats in a given sequence ofsatellite DNA they will all generate unique fragment profiles These different profilescan be compared using gel electrophoresis |
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What are two main real life applications for DNA profiling? |
1. Forensic Investigations 2. Paternity Testing |
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How are DNA profiles analyzed? |
Paternity: Child's DNA match 50% of each parent Forensic: Crime scene DNA must be a perfect match to that of a suspect DNA |
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How is genetic modification (gene transfer between species) able to be successfully carried out? |
- The genetic code is universal, for everyliving organism the same codons code for the same amino acids aka each codonproduces the same amino acid in transcription and translation regardless of thespecies (there are a few rare exceptions) - We can take genes from one species and insert them into thegenome of another species |
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What are the three main steps of basic gene transfer using plasmids? |
1. DNA extraction 2. Digestion and Ligation 3. Transfection and Expression |
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Describe what happens during the DNA extraction phase of gene transfer. |
- Plasmid is removed from bacterial cell - Gene ofinterest is removed from an organism’s genome using restriction endonucleasewhich cuts at specific sequences of DNA - The gene of interest and plasmid are amplified (PCR) |
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Describe what happens during the Digestion and Ligation phase of gene transfer. |
- Plasmid is cut with the same restrictionenzyme that was used to excise gene - Cutting with certain restriction enzymes maygenerate short sequence overhangs (“sticky ends”) that allow 2 DNA constructsto fit together - Gene of interest and plasmid are spliced together by DNA ligase(creating recombinant plasmid) |
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What are some examples of current uses of genetically modified crops? |
1. Engineeringcrops to extend shelf life of fresh produce: Flavr Savr tomatoes (ripening gene switched off) 2. Engineeringof crops to provide protection from insects: Bt Corn with added toxin 3. Salttolerant plant: Golden rice more vitamin A |
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What are some examples of current uses of genetically modified organisms? |
- Enhancing production: sheep producing more wool - Producing desired products: Milkcontaining spider silk protein is produced by goats (spider silk = immenselystrong) and Human insulin produced bybacteria for diabetes |
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List potential benefits associated with the genetic modification of crops. |
- Introduction of a new trait to the gene pool - Increased productivity/yield - Increased disease resistance - Less use of herbicides/fertilizers - Increased nutritional content |
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List potential harmful effects associated with the genetic modification of crops. |
- Could be toxic/cause allergies to unintended species - Accidental release: competition with native species - Transferred genes could mutate - Biodiversity + genetic variation reduced - Super weeds and cross breeding |
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Name and briefly explain two natural cloning techniques used in plants. |
1. Runners: Modified lateralstem used to reproduce asexually. Each new plantlet can separate to produce anew plant. Clones allow plants to quickly propagate (produce copies) of successfulplants 2. Tubers: Swollen tips ofunderground stems are storage organs in plants (like sweet potatoes). During winter, plant dies but in spring each tuber starts to growproducing separate plants, all are clones of the parent plant |
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Briefly explain the process of cloning animals at the embryo stage. |
- Embryo can split and then continue to developseparately to form identical twins - This is possible because in embryonicdevelopment, the cells are still unspecialized (can be come any type of cell) - Limited value as an artificial process as only very young embryoniccells can be used |
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Explain in detail the process of cloning adult animals using differentiated cells. |
- Process of Somatic Cell Nuclear Transfer SCNT - Female animal is treated with hormones tostimulate development of eggs, Nucleus from an egg cell is removed, therebyremoving genetic info of cell - Egg cell then fused with nucleus from asomatic cell of another animal, making the egg cell diploid. Electric shock delivered to stimulate the eggto divide (mitosis) and once process has begun, egg is implanted into uterus ofsurrogate. Developing embryo will have same genetic material as the animal thatcontributed the diploid nucleus and thus be a clone |
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Name the most well-known example of successful Somatic Cell Nuclear Transfer (SCNT). |
- Dolly the sheep: first successful cloning of amammal from a differentiated somatic cell - She was the result of many attempts,interestingly she died young but of age-related illness - Human reproductive cloning is illegal |
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What are arguments for therapeutic cloning? |
- May be used tocure serious diseases/disabilities with cell therapy - Stem cellresearch may pave way for future discoveries/beneficial technologies - Stem cell can betaken from embryos that stopped developing and would have dies anyway (ex.abortions) - Cells taken at stage when embryo has no nervous system; cannot feel pain |
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What are agreements against therapeutic cloning (also known as the ethical issues)? |
- Involves creation and destruction of human life - Embryonic cells capable of continuous division, can become cancerous - More embryos produced than needed, excess killed - Alternative technologies may fulfill similar role (with more money and effort) |
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What does each variable stand for in the Hardy-Weinberg Equations? |
- q = recessive allele/gene - p = dominant allele/gene - q2 = homologous recessive phenotype(/trait/genotype/individual) frequency - p2 = homologous dominant phenotypefrequency - 2pq = heterozygous phenotype frequency |
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What 5 assumptions are made when using the Hardy-Weinberg equation to assume that genetic equilibrium has occurred? |
1. Population is large 2. Random mating 3. No mutation 4. No gene flow (immigration/emigration) 5. No natural selection or allele-specific mortality |
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What are the four kinds of reproductive isolation of populations? |
1. Temporal: different mating seasons 2. Behavioural: different mating rituals/pheromones 3. Ecological: two species live in same area but different habitats. 4. Geographic: physical barrier or undesirable habitat before the two population |
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Convergent vs. Divergent Evolution: Similarity |
Both explain the presence of similar structures in organisms of different species |
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Convergent vs. Divergent Evolution: Differences |
- Convergence: different ancestors, analogous structures, more similar over time. Ex. wings in bats, birds. - Divergence: common ancestor, homologous structures, more different over time, adaptive radiation, leads to speciation. Ex. pentadactyl limb |
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What is stabilizing selection? Provide an example. |
- Favours theaverage forms of a trait - Ex. Lizards larger than average more visible for prey, but lizardssmaller than average can’t run as fast, can’t escape predators |
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What is directional selection? Provide an example? |
- Favours oneextreme form of a trait - Ex. Anteaterwith larger tongues have an advantage obtaining termites - NOTE: Average are still surviving mostly but now the one extreme is moresuccessful |
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What is disruption selection? Provide an example. |
- Favours bothextreme forms of a trait and NOT the average form - Ex. Shell colour on marine animals: white and dark can camouflage againstrocks but greyish shells stand out to predators |
